Process and material for preparing metal for coating



PATENT OFFICE.

I'm H. GRAYELL, OF ELKINS PARK, PENNSYLVANIA.

PROCESS AND MATERIAL FOR PREPARING METAL FOR C(lATING.

2N0 Drawing.

To all whom it may concern;

Be it known that I, JAMES H. Gmvann,

- a citizen of the United States, residing at Elkins Park, in the countyof Montgomery and State of Pennsylvania, have invented a new and usefulProcess and Material for Preparing Metal for Coating, of which thefollowing is a specification.

This invention relates to the cleaning of surfaces and although it maybe used to advantage in plating operations and washing dishes, yet it isparticularly directed to the preparation of metal for painting.

One object of the invention is to provide an improved material andprocess for removing oily coatings to produce a desirable surface. 7

According to the present practice the metal to be plated or painted istreated with a hot aqueous solution containing free hydroxyl ions toremove the oily materials and in some cases the metal is washed withwater to remove the excess solution before the coatin is applied.

I have d hydroxyl bath may be greatly improved by the addition of analcohol which boils at a higher temperature than ethyl alcohol, such forinstance as amyl or butyl alcohol. I prefer to use butyl alcohol due toits lack of objectionable odor and I will describe the invention inconnection with that material but I wish it understood that otheralcohols ma be used as equivalents.

ccording to m invention I provide a wash or bath conslsting of water inwhich is dissolved a material to generate hydroxyl ions such astrisodium phosphate and in addition an alcohol of relative high boilinpoint such for instance as butyl alcoho Although the proportions usedmay be varied to a great extent, I find the following proportionssatisfactory:

Trisodium phosphate 1.00 pound Water 4.00 gallons Butyl alcohol .20gallon consistsin treating the metal with the aboyedescribed admixtureeither hot or cold. After the work has been made as clean as iscoveredthat the action of the Application filed January 20, 1928. Serial No.614,044.

desired, it is ready for subsequent opera-.

tionsr- In case the Work is to be painted after treatment with my bath,it may .be allowed to dry, or it may be washed in water and then allowedto dry, but if it is first washed in a dilute acid and then washed inwater and allowed to dry, the acid neutralizes every trace of alkali sothat none remains on the Work to act on the paint and shorten its life.Although almost any acid can be used for this purpose, phosphoric acidproduces the best results when the metal is iron or steel because itdoes not tend to cause the metal to rust. This acid may be used in thefollowing proportions:

Phosphoric acid 1 pound Water 100 gallons The addition of the higheralcohol to the alkali bath or wash greatly improves it in that itremoves oil and dirt quicker and may be operated at a lower temperature;in

' many cases room temperatures produce satisfactory results. The acidbath or wash prevents any alkali from remaining on the work with theresult that the paint adheres better and lasts longer than when no acidbath is used.

The benefit of the doctrine of equivalents as applied in chemical casesis reserved and the invention is not limited to mere matters of form orotherwise than as the prior art and the appended claims may require.

I claim:

1. The method of cleaning metal consisting in subjectin it to the actionof an alkali metal compoun in the presence of an alcohol which boils ata higher temperature than ethyl alcohol.

2. The method of cleaning metal consisting in subjecting it to theaction of an admixture comprising butyl alcohol and trisodium phosphate.

3. The method of cleaning metal consisting in subjecting it to theaction of an admixture comprising butyl alcohol and trisodium phosphateand then washing the metal in water.

4. The method of cleaning metal consisting in subjecting it to theaction of an admixture comprising butyl alcohol and trisodium phosphateand then to the action of a dilute acid.

5. The method of cleaning metal consisting. in subjecting it to theaction of an admixture comprising butyl alcohol and trisodium phosphate,then to the action of a dilute acid, and then to the action of water. 6.A composition of matter for cleaning surfaces consisting of an admixturecon- 1 metal consisting of an admixture comprising an alkali metalcompound and butyl alcohol.

8. A composition of matter for cleaning metal consisting of an admixturecomprising trisodium phosphate and butyl alcohol.

9. A composition of matter for cleaning metal consisting of an admixturecomprising basic sodium phosphate and alcohol.

JS H. GRAVELL.

